Average Weather at Lewiston–Nez Perce County Airport Idaho, United States
At Lewiston–Nez Perce County Airport, the summers are short, hot, dry, and mostly clear and the winters are very cold and partly cloudy. Over the course of the year, the temperature typically varies from 30°F to 93°F and is rarely below 18°F or above 102°F.
Based on the tourism score, the best time of year to visit Lewiston–Nez Perce County Airport for warm-weather activities is from early July to late August.
The hot season lasts for 2.6 months, from June 22 to September 10, with an average daily high temperature above 82°F. The hottest day of the year is August 2, with an average high of 93°F and low of 64°F.
The cold season lasts for 3.4 months, from November 12 to February 23, with an average daily high temperature below 50°F. The coldest day of the year is December 22, with an average low of 30°F and high of 40°F.
Average High and Low Temperature
The figure below shows you a compact characterization of the entire year of hourly average temperatures. The horizontal axis is the day of the year, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.
Average Hourly Temperature
At Lewiston–Nez Perce County Airport, the average percentage of the sky covered by clouds experiences significant seasonal variation over the course of the year.
The clearer part of the year at Lewiston–Nez Perce County Airport begins around June 15 and lasts for 3.8 months, ending around October 8. On July 29, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 81% of the time, and overcast or mostly cloudy 19% of the time.
The cloudier part of the year begins around October 8 and lasts for 8.2 months, ending around June 15. On January 15, the cloudiest day of the year, the sky is overcast or mostly cloudy 65% of the time, and clear, mostly clear, or partly cloudy 35% of the time.
Cloud Cover Categories
0% clear 20% mostly clear 40% partly cloudy 60% mostly cloudy 80% overcast 100%
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days at Lewiston–Nez Perce County Airport varies throughout the year.
The wetter season lasts 8.0 months, from October 21 to June 20, with a greater than 23% chance of a given day being a wet day. The chance of a wet day peaks at 38% on November 28.
The drier season lasts 4.0 months, from June 20 to October 21. The smallest chance of a wet day is 8% on August 5.
Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 35% on November 19.
Daily Chance of Precipitation
To show variation within the months and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day of the year. Lewiston–Nez Perce County Airport experiences some seasonal variation in monthly rainfall.
The rainy period of the year lasts for 12 months, from August 9 to July 29, with a sliding 31-day rainfall of at least 0.5 inches. The most rain falls during the 31 days centered around November 22, with an average total accumulation of 2.2 inches.
The rainless period of the year lasts for 1.6 weeks, from July 29 to August 9. The least rain falls around August 3, with an average total accumulation of 0.5 inches.
Average Monthly Rainfall
The sliding 31-day liquid-equivalent quantity of snowfall at Lewiston–Nez Perce County Airport does not vary significantly over the course of the year, staying within 0.1 inches of 0.1 inches throughout.
Average Liquid-Equivalent Monthly Snowfall
The length of the day at Lewiston–Nez Perce County Airport varies significantly over the course of the year. In 2018, the shortest day is December 21, with 8 hours, 36 minutes of daylight; the longest day is June 21, with 15 hours, 48 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 4:55 AM on June 15, and the latest sunrise is 2 hours, 37 minutes later at 7:32 AM on November 3. The earliest sunset is at 4:01 PM on December 10, and the latest sunset is 4 hours, 43 minutes later at 8:44 PM on June 26.
Daylight saving time (DST) is observed at Lewiston–Nez Perce County Airport during 2018, starting in the spring on March 11, lasting 7.8 months, and ending in the fall on November 4.
Sunrise & Sunset with Twilight and Daylight Saving Time
The perceived humidity level at Lewiston–Nez Perce County Airport, as measured by the percentage of time in which the humidity comfort level is muggy, oppressive, or miserable, does not vary significantly over the course of the year, remaining a virtually constant 0% throughout.
Humidity Comfort Levels
dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
The average hourly wind speed at Lewiston–Nez Perce County Airport experiences mild seasonal variation over the course of the year.
The windier part of the year lasts for 7.1 months, from October 23 to May 27, with average wind speeds of more than 6.4 miles per hour. The windiest day of the year is March 27, with an average hourly wind speed of 7.1 miles per hour.
The calmer time of year lasts for 4.9 months, from May 27 to October 23. The calmest day of the year is August 11, with an average hourly wind speed of 5.6 miles per hour.
Average Wind Speed
The predominant average hourly wind direction at Lewiston–Nez Perce County Airport varies throughout the year.
The wind is most often from the west for 7.7 months, from March 5 to October 27, with a peak percentage of 57% on June 21. The wind is most often from the south for 4.3 months, from October 27 to March 5, with a peak percentage of 53% on January 1.
Best Time of Year to Visit
To characterize how pleasant the weather is at Lewiston–Nez Perce County Airport throughout the year, we compute two travel scores.
The tourism score favors clear, rainless days with perceived temperatures between 65°F and 80°F. Based on this score, the best time of year to visit Lewiston–Nez Perce County Airport for general outdoor tourist activities is from early July to late August, with a peak score in the first week of August.
The beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best time of year to visit Lewiston–Nez Perce County Airport for hot-weather activities is from mid July to mid August, with a peak score in the last week of July.
For each hour between 8:00 AM and 9:00 PM of each day in the analysis period (1980 to 2016), independent scores are computed for perceived temperature, cloud cover, and total precipitation. Those scores are combined into a single hourly composite score, which is then aggregated into days, averaged over all the years in the analysis period, and smoothed.
Our cloud cover score is 10 for fully clear skies, falling linearly to 9 for mostly clear skies, and to 1 for fully overcast skies.
Our precipitation score, which is based on the three-hour precipitation centered on the hour in question, is 10 for no precipitation, falling linearly to 9 for trace precipitation, and to 0 for 0.04 inches of precipitation or more.
Our tourism temperature score is 0 for perceived temperatures below 50°F, rising linearly to 9 for 65°F, to 10 for 75°F, falling linearly to 9 for 80°F, and to 1 for 90°F or hotter.
Our beach/pool temperature score is 0 for perceived temperatures below 65°F, rising linearly to 9 for 75°F, to 10 for 82°F, falling linearly to 9 for 90°F, and to 1 for 100°F or hotter.
The growing season at Lewiston–Nez Perce County Airport typically lasts for 7.2 months (221 days), from around March 26 to around November 3, rarely starting before February 28 or after April 19, and rarely ending before October 12 or after November 25.
Time Spent in Various Temperature Bands and the Growing Season
Based on growing degree days alone, the first spring blooms at Lewiston–Nez Perce County Airport should appear around April 7, only rarely appearing before March 24 or after April 22.
Growing Degree Days
The average daily incident shortwave solar energy experiences extreme seasonal variation over the course of the year.
The brighter period of the year lasts for 3.1 months, from May 20 to August 22, with an average daily incident shortwave energy per square meter above 6.4 kWh. The brightest day of the year is July 15, with an average of 7.6 kWh.
The darker period of the year lasts for 3.7 months, from October 27 to February 18, with an average daily incident shortwave energy per square meter below 2.5 kWh. The darkest day of the year is December 23, with an average of 1.2 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Lewiston–Nez Perce County Airport are 46.374 deg latitude, -117.015 deg longitude, and 1,171 ft elevation.
The topography within 2 miles of Lewiston–Nez Perce County Airport contains significant variations in elevation, with a maximum elevation change of 778 feet and an average elevation above sea level of 1,213 feet. Within 10 miles contains significant variations in elevation (2,365 feet). Within 50 miles contains large variations in elevation (5,741 feet).
The area within 2 miles of Lewiston–Nez Perce County Airport is covered by grassland (31%), artificial surfaces (30%), and shrubs (28%), within 10 miles by grassland (38%) and cropland (36%), and within 50 miles by shrubs (33%) and cropland (32%).
This report illustrates the typical weather at Lewiston–Nez Perce County Airport, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.
Temperature and Dew Point
Lewiston–Nez Perce County Airport has a weather station that reported reliably enough during the analysis period that we have included it in our network. When available, historical temperature and dew point measurements are taken directly from this weather station. These records are obtained from NOAA's Integrated Surface Hourly data set, falling back on ICAO METAR records as required.
In the case of missing or erroneous measurements from this station, we fall back on records from nearby stations, adjusted according to typical seasonal and diurnal intra-station differences. For a given day of the year and hour of the day, the fallback station is selected to minimize the prediction error over the years for which there are measurements for both stations.
The stations on which we may fall back include but are not limited to Pullman–Moscow Regional Airport, Idaho County Airport, Walla Walla Regional Airport, Felts Field, Spokane International Airport, Coeur D'Alene Air Terminal, Fairchild Air Force Base, and Lowell.
Time zones for aiports and weather stations are provided by AskGeo.com .